Isaac ben Judah ibn Ghiyyat (or Ghayyat) (Hebrew: יצחק בן יהודה אבן גיאת|Yīṣḥāq ben Yəhūdā ʾībən Gāyyat, Arabic: ﺇﺑﻦ غیات|ibn Ghayyāth[1]) (1030/1038–1089) was a Spanish rabbi, Biblical commentator, codifier of Jewish law, philosopher, and liturgical poet. He was born and lived in the town of Lucena, where he also headed a rabbinic academy. He died in Cordoba.
As most Spanish Jewish surnames, ibn Ghayyat is a nasab or Arabic patronymic, "the son of Ghayyāth." Ghayyāth means "salvation" in Arabic and is found in Saadia Gaon's Judeo-Arabic translation of Hebrew: יֵשַׁע|yēshaʿ|salvation in Psalm 20:7, "Now I know that YHWH will give victory to His anointed, will answer him from His heavenly sanctuary with the might of salvation in His right arm (בג'ברואת גיאת' ימינה)."[2]
According to some authorities, he was the teacher of Isaac Alfasi; according to others, his fellow pupil. His best-known students were his son Judah ibn Ghayyat, Joseph ibn Sahl, and Moses ibn Ezra. He was held in great esteem by Samuel ibn Naghrillah and his son Joseph, and after the latter died in the 1066 Granada massacre, ibn Ghayyat was elected to succeed him as rabbi of Lucena, where he officiated until his death.
He was the author of a compendium of ritual laws concerning the festivals, published by Seligman Baer Bamberger under the title of Sha'arei Simḥah (Fürth, 1862; the laws concerning Passover were republished by Bernhard Zomber under the title Hilkhot Pesaḥim, Berlin, 1864), and a philosophical commentary on Ecclesiastes, known only through quotations in the works of later authors.[3]
Ibn Ghayyat's greatest activity was in liturgical poetry; he was an author of hundreds of piyyutim, and his hymns are found in the Maḥzor of Tripoli under the title of Siftei Renanot. Most are written in the new Andalusian style. He achieved special distinction in his melodious muwashshaḥat "girdle poems", a secular Arabic form first used as a vehicle for liturgical poetry by Solomon ibn Gabirol.[4]
One of his major contributions was his collection and arrangement of the geonic responsa which had hitherto been scattered among the world's Jewry.[5]